The following references are believed to represent the state of the art:    A paper by Ding Yi entitled “A New Obfuscation Scheme in Constructing Fuzzy Predicates,” World Congress on Software Engineering, vol. 4, pp. 379-382, 19-21 May 2009;    U.S. Pat. No. 6,668,325 to Collberg, et al.;    US Published Patent Application 2005/0183072 of Horning et al.;    US Published Patent Application 2006/0253687 of Jakubowski et al.;    US Published Patent Application 2008/0028474 of Horne et al.;    US Published Patent Application 2008/0208560 of Johnson et al.;    US Published Patent Application 2009/0296922 of Smeets et al.; and    US Published Patent Application 2010/0199354 of Eker et al.